Production plant having a protective unit

ABSTRACT

The invention relates to a production installation (1) for bending sheet metal comprising a bending press (3) with press beams (13, 16), a bending tool (4), a tool manipulation unit (30) for the bending tool (4), and a protective unit (29) with a protective element (32) and an adjusting device (33, 44). The protective element (32) of the protective unit (29) can be moved from a protective position which covers the bending tool (4) into a release position which releases the bending tool (4). The adjusting device (33) comprises at least two brackets (37) and at least two holding arms (38), the protective element (32) being mounted on the brackets (37) in an articulated manner by means of the holding arms (38). The adjusting device (44) can also comprise at least two linear guide arrangements (45) each having a plurality of guide rails (46, 47, 48), by means of which the protective element (32) can be displaced between the two positions.

The invention relates to a production installation, in particular forair bending of workpieces to be manufactured from sheet metal, with aprotective unit comprising at least one protective element, which servesin particular for covering of its bending tool during tool change asneeded.

U.S. Pat. No. 3,186,256 A describes a bending machine for manufacturingworkpieces or parts between at least one bending tool adjustablerelative to one another. The bending tool comprises a bending punch anda bending die, which are each held on a press beam. For carrying out thebending operation, one of the press beams is guided adjustably in thevertical direction on a machine frame. On the operating side, and thuson the side by which the sheet metal to be bended is guided, aplate-shaped protective element is arranged upstream of the bendingtool. For mounting the protective element, a support rod is provided,which is mounted on side walls of the machine frame located laterally ofthe press beams. The support rod is arranged above the protectiveelement and carries several actuator elements, which are connectedthereto for vertical displacement of the protective element. Theadjusting stroke of the actuator elements between the protectiveposition and the release position is limited by the relatively shortadjusting track of the actuator elements formed as electro magnets. Thevertical adjustment of the protective element serves for not forming aninterference contour for the portion of the workpieces to bemanufactured which is pivoted upwards during the bending operation.Furthermore, with this, it is not possible to create sufficient freespace in front of the bending tool in all cases of operation.

Another design of a protective element for a bending machine formanufacturing workpieces or parts between at least one bending tooladjustable relative to one another has become known from U.S. Pat. No.3,969,955 A. The bending tool comprises a bending punch and a bendingdie, which are each held on a press beam. For carrying out the bendingoperation, one of the press beams is guided adjustably in the verticaldirection on a machine frame. The plate-shaped protective element isheld on the upper adjustable press beam by at least two hingearrangements arranged at a distance from one another on a flat profilewith an elongated hole arranged therein. The flat profiles can beadjusted relative to the upper press beam in the vertical direction byprovision of the elongated holes respectively arranged therein.Additionally, if need be, the protective element can be pivoted forwardtowards the operating side or folded up by means of the hingearrangement. Here, merely a small vertical adjustment stroke could beachieved. Also with the protective element folded up, no sufficient freespace without the formation of an interfering contour could be created.

A further design of a protective element for a bending machine isdescribed in U.S. Pat. No. 4,030,364 A. The upper press beam isadjustable in the vertical direction relative to the fixed machineframe. The plate-shaped protective element is held on a carrier elementof the machine frame arranged fixedly above the upper press beam in itslowermost position by means of retaining cables. In this lowermostposition of the protective element, there is a feed gap for the sheetmetal to be bent formed small as regards its height. By means of amultiply deflected pulley, the protective element can be elevated duringthe downward movement of the upper press beam in the course of thebending operation. One end of the cable of the pulley is fixedlyconnected to the protective element and the other end is fixedlyconnected to the press beam. A double deflection of the cable of thepulley is carried out on the carrier element, wherein further, adeflection provided for between these two is carried out on the backsideof the upper press beam. When the upper press beam moves in thedirection towards the lower press beam, the protective element iselevated relative to the lower press beam, whereby the previously smallfeed gap increases in height. The disadvantage of this is that anadjusting movement of the protective element is only possible when theupper press beam is adjusted and the adjusting movement of theprotective element depends on the adjusting stroke of the upper pressbeam. Moreover, the pulley arranged is complex and not always reliablein operation.

JPH 11-300421 describes a further design of a protective device with aplate-shaped protective element for a bending machine. In the region offixed side walls of the machine frame, a pulley for adjusting the heightof the protective element is provided respectively. Starting out fromthe protective element, each of the pulleys extends in the verticaldirection to a first deflection roller, from the latter to a seconddeflection roller located in the region of the backside of the sidewalls and from the latter to an actuator element formed by a cylinderpiston arrangement. The possible adjustment track of the protectiveelement is determined by the adjusting stroke of the actuator elements.The disadvantage of this is the unstable arrangement of the protectiveelement in all of its positions.

Another protective device adjustable in the vertical direction on aninstallation has become known from JPH 06-34736 U. In the region of bothlongitudinal ends of the protective device, above each of these a drivenroller is arranged. A pull rope is wound around each of the rollers,wherein a first end of the pull rope is connected to the protectivedevice and a second end is connected to a counterweight, respectively.By the drive torque applied onto the two rollers and by means of supportof the counterweight, the protective device can be easily adjusted inthe vertical direction from its protective position into the releaseposition. For this purpose, several installation components are to beprovided for the adjusting mechanism, an unstable arrangement of theprotective element due to the pulley and further, the possibility ofcreating interfering contours being given.

It was the object of the present invention to overcome the shortcomingsof the prior art and to provide a device by means of which it ispossible to allow for secure and easy covering of the hazard area duringtool change and not forming an interfering contour in the releaseposition of the protective element during performance of the bendingoperation.

This object is achieved by means of a production installation, inparticular with the protective unit provided for this purpose, accordingto the claims.

The production installation according to the invention can in particularserve for air bending or bottom bending of a workpiece to bemanufactured from sheet metal, and comprise the following installationcomponents:

-   -   a bending press, in particular a press brake, with a machine        frame, a lower press beam, an upper press beam as well as tool        holders arranged or formed on the press beams,    -   at least one bending tool with at least one bending punch and at        least one bending die,    -   a tool manipulation unit for moving the bending tool between the        tool holders and a tool storage or for changing the position of        the bending tool relative to the tool holders,    -   a protective unit with at least one protective element and an        adjusting device, by means of which adjusting device the at        least one protective element can be displaced relative to the        bending press from a protective position which at least        sectionally covers the bending tool into a release position        which at least sectionally releases the bending tool, and the at        least one protective element is plate-shaped and comprises a        first longitudinal edge as well as a second longitudinal edge        and a width of the protective element is defined by the two        longitudinal edges, and wherein the protective unit is arranged        in a feed region in front of the bending press, wherein    -   either the adjusting device comprises at least two brackets and        at least two holding arms each having a first end region and a        second end region, and the holding arms each being mounted on        the brackets in an articulated manner with their first end        regions and the holding arms each being connected to the at        least one protective element on its first longitudinal edge        facing away from the first press beam in an articulated manner        with their second end regions, and the at least two brackets        being arranged at a distance from one another in the direction        of the longitudinal extent of the at least one protective        element,    -   or the adjusting device comprises at least two linear guide        arrangements, and each of the linear guide arrangements        comprises a first guide rail and a second guide rail and at        least one further guide rail, and the first guide rails are each        arranged stationarily on the bending press, and each of the at        least one further guide rails is mounted on the at least one        protective element, and the at least two linear guide        arrangements are arranged at a distance from one another in the        direction of the longitudinal extent of the at least one        protective element.

The advantage achieved by this consists in that depending on theselection of the adjusting device, a sufficiently long adjustment trackfor the at least one protective element between its protective positionand its release position is provided. Hence, a secure covering in thefront region between the opened press beams with the bending toolarranged thereon can be achieved for the protective position. When theat least one protective element is adjusted into its release position,it is adjusted to be so far from the bending tool held on the pressbeam, owing to the adjustment track selected to be sufficiently long,that no interfering contour for the performance of bending operations isformed by the protective element.

By providing the brackets as the bearing basis and the holding arms orlever arms held thereon in an articulated manner, when the protectiveelement is pivoted up from the protective position into the releaseposition an adjustment track defined by the longitudinal extension ofthe holding arms can be provided for, with which the at least oneprotective element can be moved out of the working area. Moreover,hence, an arrangement of the at least one protective element preferablysuspended in all operating positions on the respective holding arms canbe achieved.

Also in a further possible embodiment of the adjusting device in theform of linear guide arrangements each comprising several guide rails, aspace-saving adjusting device, which allows for a straight adjustingmovement, in particular by means of a telescopic guide, can hence becreated. By providing several guide rails, hence, starting out from therelease position into the protective position and back, a sufficientlylong adjustment track can be created so as to again on the one hand forma secure covering of the bending tool during tool change and on theother hand no interfering contour when the protective element is locatedin the release position during the bending operation.

In a further possible embodiment, it is provided for that the protectiveunit, in particular its brackets or its first guide rails, is held onthe upper press beam. Due to the fact that the entire protective unit isheld on the upper press beam such that it moves therewith, the entireprotective unit is always moved with it and the relative distancebetween the upper press beam and the protective unit, in particular theprotective element, in the release position is kept equal. If hence, therelative position has once been determined in the release position, nointerfering contour located closer is created in subsequent bendingoperations.

It can further be advantageous if the width of the at least oneprotective element between its two longitudinal edges corresponds to anopening width between the tool holders of the completely open bendingtool. Hence, secure covering of the hazard area during the tool changecan be achieved. Moreover, hence, the headroom and/or width of theprotective element can also be kept as low as possible.

Another embodiment is characterized in that the at least two holdingarms are pivotable between the protective position and the releaseposition of the at least one protective element, each by a pivot anglewith a value selected from an angle range with a lower limit of 150° andan upper limit of 200°, in particular 180°. By providing a sufficientlylarge pivot angle of the holding arms, on the one hand a space-savingarrangement of the adjusting device both in the protective position andin the release position can be ensured and on the other hand a distanceof the protective element from the bending region in the releaseposition can be achieved.

A further possible embodiment has the characteristics of a longitudinalextension of the holding arms each approximately corresponding to thewidth of the at least one protective element between its twolongitudinal edges. Hence, also in case of minimum widths of theprotective element, a sufficient adjustment track can be achieved and acompact constructional unit can, nevertheless, be created.

In a further embodiment, it is provided for that in the releaseposition, the holding arms each starting out from the brackets projecttowards the side facing away from the lower press beam and the at leastone protective element is arranged so as to be suspended on the side ofthe holding arms facing away from the upper press beam as well as in thedirection towards the lower press beam. Hence, by the holding armspivoted up and the arrangement of the at least one protective elementsuspended thereon, a space-saving arrangement of the protective elementin the pivoted-up release position can be achieved.

Another embodiment is characterized in that in the protective position,both the holding arms starting out from the brackets and the at leastone protective element connected to the holding arms in an articulatedmanner comprise a suspended arrangement in the direction towards thelower press beam. Hence, a change of position of the protective elementbetween its release position and its protective position by double thelongitudinal extension of the holding arms can be achieved.

A further preferred embodiment is characterized in that the brackets arearranged on the upper press beam such that in the protective positionand with the bending tool being completely open, the second longitudinaledge of the at least one protective element faces the lower press beamand the at least one protective element with its second longitudinaledge extends at least to the lower tool holder. Hence, one the one handin the release position secure covering also with the bending tool beingopen and on the other hand a sufficiently large distancing in therelease position can be achieved.

It can further be advantageous if the at least two brackets are arrangedin an upper end section of the upper press beam. Upper end section orend region of the press beam is understood such that the brackets arearranged in the region which is distanced farther from the lower pressbeam. Hence, the possibility of arranging the at least one protectiveelement at a rather large distance from the bending tool in its releaseposition is created. The interfering contour formed by the protectiveelement can thus be arranged very far from the bending region of thesheet metal. Further, sufficient free space without limitations causedby the protective element is thus also formed on the operating side orfeed side.

Another alternative embodiment variant is characterized in that at leastone actuator and/or damping device is provided, said at least oneactuator and/or damping device being operatively connected to one of theholding arms. Hence, by providing at least one actuator and/or dampingdevice, a controlled pivoting movement of the holding arm(s) can beachieved.

Moreover, hence, a facilitation of the return movement from theprotective position into the release position in case of manualadjustment by the operator can be achieved. However, by means of theactuator device, a counterbalance adjustment and a corresponding weightcompensation can also be achieved. By means of the damping device, thedownward movement of the holding arm(s) from the upwardly projectionposition into the downwardly projecting position can be decelerated.Hence, a controlled downward movement of the holding arms along with theprotective element held thereon can be achieved.

In a further embodiment, it is provided for that a maximum adjustmenttrack of the at least two linear guide arrangements is selected suchthat in the protective position and with the bending tool beingcompletely open, the second longitudinal edge of the at least oneprotective element faces the lower press beam and the at least oneprotective element with its second longitudinal edge extends at least tothe lower tool holder. By selecting the maximum adjustment track, hence,a precisely predefined operating state of the protective unit in each ofits positions can be achieved. Moreover, hence, secure covering can alsobe ensured in the protective position, while in the release position, byprovision of multiple guide rails the protective element can be movedout of the bending region of the bending tool far enough and thus nointerfering contour is formed by it any more.

A further possible and optionally alternative embodiment has thecharacteristics that the at least two linear guide arrangements are heldon the upper press beam in vertical orientation. Hence, a precisestraight adjusting movement between the protective position and therelease position can be achieved. By means of constant movement of theentire protective unit with the upper press beam, the relative distancein the release position between the upper press beam and the protectiveunit, in particular the protective element, can always be kept equal. Ifhence, the relative position has once been determined in the releaseposition, no interfering contour located closer is created in subsequentbending operations.

Another embodiment is characterized in that at least one drive elementis provided on at least one of the linear guide arrangements. Byproviding at least one drive element, a controlled adjusting movementfrom the release position to the protective position and/or from theprotective position to the release position can be achieved in theadjusting operation.

A further preferred embodiment is characterized in that one of the driveelements is provided between the first guide rail and the second guiderail. Hence, a precisely predetermined adjusting movement between thefirst two guide rails can be achieved.

It can further be advantageous if one of the drive elements is providedbetween the second guide rail and the at least one further guide rail.Hence, a consistent adjusting movement between the individual guiderails can be ensured.

Lastly, another embodiment is characterized in that at least oneactuator and/or damping device is provided, said at least one actuatorand/or damping device being operatively connected to the at least oneprotective element. Hence, by providing at least one actuator and/ordamping device, a controlled pivoting movement of the holding arm(s) canbe achieved. Moreover, hence, a facilitation of the return movement fromthe protective position into the release position in case of manualadjustment by the operator can be achieved. However, by means of theactuator device, a counterbalance adjustment and a corresponding weightcompensation can also be achieved. By means of the damping device, thedownward movement of the holding arm(s) from the upwardly projectionposition into the downwardly projecting position can be decelerated.Hence, a controlled downward movement of the holding arms along with theprotective element held thereon can be achieved.

For the purpose of better understanding of the invention, it will beelucidated in more detail by means of the figures below.

These show in a respectively very simplified schematic representation:

FIG. 1 a front view of a production installation with a bending pressand schematically adumbrated protective unit;

FIG. 2 a side view of the production installation according to FIG. 1;

FIG. 3 a front view and schematic representation of a first possibledesign of the protective unit in its protective position with adumbratedbending press;

FIG. 4 a side view of the protective unit according to FIG. 3 in itsprotective position;

FIG. 5 a side view of the protective unit according to FIG. 3, however,in its release position;

FIG. 6 a front view and schematic representation of a further possibledesign of the protective unit in its protective position with adumbratedbending press;

FIG. 7 the protective unit according to FIG. 6 in a top view onto theadjusting device.

First of all, it is to be noted that in the different embodimentsdescribed, equal parts are provided with equal reference numbers and/orequal component designations, where the disclosures contained in theentire description may be analogously transferred to equal parts withequal reference numbers and/or equal component designations. Moreover,the specifications of location, such as at the top, at the bottom, atthe side, chosen in the description refer to the directly described anddepicted figure and in case of a change of position, thesespecifications of location are to be analogously transferred to the newposition.

The term “particularly/in particular” is hereinafter understood suchthat it may refer to a possible, more specific embodiment and moredetailed specification of a subject matter or a method step, but doesnot necessarily have to represent an obligatory, preferred embodiment ofthe latter or an approach.

FIGS. 1 and 2 show a very simplified schematic representation of aproduction installation 1, which is in particular designed for airbending of workpieces 2 to be manufactured from sheet metal by means ofdie bending in the present case.

The production installation 1 used for bending in the present casecomprises a bending machine, in the present exemplary embodiment abending press 3, in particular a press brake oder die bending press, formanufacturing the workpieces 2 or parts between at least one bendingtool 4 adjustable relative to one another. In the present exemplaryembodiment, the bending tool 4 comprises at least one bending punch 5,however, most commonly several bending punches 5, and at least onebending die 6, however, most commonly several bending dies 6 cooperatingtherewith. At this, the at least one bending punch 5 is arranged abovethe workpiece 2 to be manufactured on the bending press 3 and is held,in particular clamped, there correspondingly. The at least one bendingdie 6 is also held, in particular held clamped, on the bending press 3.

In a coordinate system for such bending presses 3, the “x” direction isgenerally referred to as the direction extending in perpendicularorientation in a horizontal plane with respect to the longitudinalextension of the bending tool 4, in particular its bending punch 5 andbending die 6. Thus, this is the direction which corresponds to the feeddirection or the removal direction. The “y” direction is understood asthe vertical direction which thus extends in the height direction of thebending tool 4, and further in perpendicular direction with respect tothe horizontal plane. Lastly, the “z” direction is understood as thedirection which extends in the longitudinal direction and/or thelongitudinal extension of the bending tool 4, in particular its bendingpunch 5 and bending die 6. Hence, the longitudinal extension of thebending edge defined by the bending tool 4 is also oriented extending inthe “z” direction.

A machine frame 7 of the bending press 3 for example comprises a baseplate 8 on which side walls 9, 10 are arranged, which rise vertically,are transversely spaced from one another and are oriented in parallel toone another. These are preferably connected to one another by a massivecross connection 11 for example formed from a sheet metal preform ontheir end regions distanced from the base plate 8.

The side walls 9, 10 can be formed approximately in a C-shape for theformation of a free space for forming the workpiece 2, wherein a fixedfirst press beam 13 or lower press beam 13, particularly standing on thebase plate 8, is mounted to front end faces 12 of near-base limbs of theside walls 9, 10. This stationarily arranged and fixed press beam 13 mayalso be referred to as press table, which parts of the bending tool 4are arranged on and also held on.

On front end faces 14 of limbs distanced from the base plate 8, afurther press beam 16, in particular a pressure beam, adjustablerelative to the press beam 13 forming the table beam, is mounted in aguided manner in linear guides 15. The press beam 16 can also bereferred to as second press beam or upper press beam or as pressurebeam.

On end faces 17, 18 opposing one another and extending in parallel toone another of the two press beams 13, 16, tool mounts 19, 20 forequipping with the bending tool(s) 4 may be arranged. The bendingtool(s) 4 can also be held on the tool holders 19, 20 with interpositionof an adapter which is not represented in more detail herein; while thisis rather considered not favorable for a change operation of individualcomponents or the entire bending tool 4, it can still represent apossibility.

The shown bending press 3 for example comprises two driving means 22operated with electric energy, which are line-connected with acontroller 24 supplied from an energy grid 23, as driving arrangement 21for the adjustable press beam 16, namely the pressure beam. For example,the operation of the bending press 3, in particular also the changeoperation of the bending tool 4, can be controlled via an input terminal25 with a communication connection to the controller 24.

The driving means 22 can for example be electromotive spindle drives 26,as are generally known, by means of which adjusting means 27 for areversible adjusting movement of the upper press beam 16 formed by thepressure beam are for example drive-connected to it. However,independently of this, it would also be possible that the driving means22 is/are formed by adjusting means that can be hydraulically and/orpneumatically actuated. In this regard, cylinder-piston arrangements maybe applied. However, other driving means, such as eccentric drives,toggle lever drives, rack and pinion drives etc., are also conceivable.Further details required for the operation of such a bending press 3,such as feed devices and/or control devices, are not addressed in thepresent description so as to avoid an unnecessary length of thedescription.

For application and support of the sheet metal to be bent, a supporttable 28 can be provided or arranged in the front region—i.e. the feedregion—of the bending press. The support table 28 is merely shownpartially and forms a support plane for the sheet metal to be bent.

Moreover, the production installation 1 can also comprise a manipulatornot represented in further detail here, said manipulator removing atleast one piece from a storage stack of sheet metal to be formed and/orfolded and transports it into the working area and/or the operating sideof the bending press 3.

The manipulator can itself comprise gripping pliers, which in turncomprises gripping fingers. The gripping fingers each comprise clampingsurfaces on the side facing the workpiece 2 to be manufactured. By meansof corresponding pivoting of the two gripping fingers against oneanother and the application of a sufficient clamping force, via thecooperation of the clamping surfaces the sheet metal and/or workpiece 2to be manufactured is held by the manipulator and correspondingly movedand positioned. By the gripping fingers and the gripping pliers,corresponding gripping and in further consequence due to the clampingmovement sufficient purchase for the workpiece 2 to be manufactured fromthe sheet metal is ensured.

It is further adumbrated that in the region of the operating side or thefeed side of the bending press 3 and thus as required in front of thebending tool(s) 4, a protective unit 29 can be arranged or provided. Theprotective unit 29 serves the purpose of covering the opening widthbetween the tool holders 19, 20 with the bending tool 4 being completelyclosed in the region of the operating side or the feed side so far thatduring the tool change, the operator is prevented from an unintendedaccess to the tool holders and the bending tool 4 located there. In thisexemplary embodiment, the upper press beam 16 is adjustable relative tothe lower press beam 13 for performing the bending operation. For toolchange, the upper press beam 16 is arranged distanced farther from thelower press beam 13, as is well-known.

Most commonly, the tool change is carried out on the back side of thepress beams 13, 16 by means of a tool manipulation unit 30 adumbrated ina simplified manner Hence, the operator can get very close to the frontregion of the bending press 3 and thus into the region of the bendingtool 4, due to which in case of inattention an injury can be caused bymoved tool components or the tool manipulation unit 30. The toolmanipulation unit 30 serves for transporting the bending tool 4 betweenthe tool holders 19, 20 and a tool storage 31 or for changing theposition of the bending tool 4 relative to its position on the toolholders 19, 20.

The protective unit 29 comprises at least one plate-shaped protectiveelement 32. Said element is usually formed from a translucent ortransparent material, in particular a plastic material. The protectiveelement 32 is arranged immediately upstream of the second or upper pressbeam 16 in both FIGS. 1 and 2, wherein it is in a so-called releaseposition represented in dotted lines in both figures. Moreover, theprotective element 32 is also represented in a so-called protectiveposition in full lines in FIG. 1. A detailed representation of themount, the bearing and a possible adjusting mechanism thereof on thebending press 3, in particular on the second or upper press beam 16, isrefrained from, while a possible embodiment in this regard isrepresented and elucidated in further detail below in FIGS. 3 to 5 aswell as 6 and 7. Herein, the release position is understood such thatthe protective element 32 allows for free access to the bending tool 4held on the press beams 13, 16.

The protective position is given when the at least one protectiveelement 32, in case of bending punch 5 and bending die 6 being arrangeddistanced from one another at least sectionally or entirely, covers orsecures an access starting out from the operating side or feed side sofar that an operator cannot reach between the open press beams 13, 16arranged at a distance from one another during a tool change of thebending tool 4. The tool change can preferably be carried outautomatically, with this usually being carried out in the region of themachine frame 7 located behind the operating side. The performance ofthe tool change can for example be carried out by means of the toolmanipulation unit 30, in particular by means of a separate manipulatorand/or a back gauge unit, as is well-known.

When the at least one protective element 32 is located in its releaseposition, in which the bending operation(s) are usually carried out,sufficient manipulation space is to be kept free of interfering contoursat least in the region of the bending tool 4. An interfering contour canbe formed by an installation component or a machine component, whichprojects into the working space required for performing the bendingoperation and thus prevents or limits it.

The adjustment or displacement of the at least one protective element 32can be carried out by means of an adjusting device 33 not represented infurther detail in FIGS. 1 and 2. By means of this adjusting device 33,the at least one protective element 32 can be displaced relative to thebending press 3 from a protective position, which at least sectionally,preferably completely, covers the bending tool 4 into a release positionwhich at least sectionally, preferably completely, releases the bendingtool 4. The displacement can be carried out manually; however, also bymeans of a separate driving means.

The plate-shaped protective element 32 comprises a first longitudinaledge 34 as well as a second longitudinal edge 35 arranged so as toextend in the direction of its longitudinal extension. The twolongitudinal edges 34, 35 define a width 36 of the protective element32. The width 36 can also be referred to as transverse distance, whichis determined in perpendicular direction with respect to thelongitudinal edges 34, 35 most commonly extending in parallel to oneanother. The longitudinal extension of the protective element 32 ispreferably selected such that it approximately corresponds to alongitudinal extension of the press beams 13, 16 or the tool holders 19,20 arranged thereon. The protective unit 29, in particular the at leastone protective element 32 as well as the adjusting device 33, is or arearranged in a feed region in front of the bending press 3. Accordingly,the arrangement is carried out frontally with respect to the bendingpress 3. In the possible embodiments described in more detail below, theprotective unit 29 is held on the upper press beam 16. Hence, when theupper press beam 16 is adjusted, the protective unit 29 is moved withit.

FIGS. 3 to 5 show a first possible and possibly independent embodimentof the protective unit 29, wherein equal reference numbers and/orcomponent designations are used for equal parts as in FIGS. 1 and 2above. In order to avoid unnecessary repetitions, it is pointedto/reference is made to the detailed description in FIGS. 1 and 2preceding it.

To provide a better overview, the two press beams 13, 16 are merelyadumbrated partially. Moreover, the adjusting device 33 is merelyrepresented in a simplified and stylized manner. The adjusting device 33comprises at least two brackets 37 and preferably the same amount ofholding arms 38—in the present example also at least two holding arms38. The holding arm 38 can also be referred to as lever arm or pivotingarm. Each of the holding arms 38 comprises a first end region 39 andarranged at a distance thereof in its longitudinal extension a secondend region 40. Each of the brackets 37 is arranged for example on themachine frame 7 of the bending press 3, however, in particular on theupper press beam 16 of the bending press 3, in particular fixedlyconnected thereto, and arranged at a distance from one another in thedirection of the longitudinal extension of the at least one protectiveelement 32.

Each of the holding arms 38 is mounted on one of the brackets 37 in anarticulated manner each with its first end region 39, whereby a firstbearing point is formed respectively. Moreover, each of the holding arms38 is connected to the at least one protective element 32 on the firstlongitudinal edge 34 facing away from the first press beam 13 in anarticulated manner with its second end region 40, whereby a secondbearing point is formed respectively. By means of these articulatedconnections, on the one hand the holding arms 38 can be pivoted aboutthe respective bracket 37 and on the other hand the at least oneprotective element 32 can be adjusted with these preferably in asteadily suspended arrangement.

The previously described width 36 of the at least one protective element32 between its two longitudinal edges 34, 35 approximately correspondsto an opening width between the tool holders 19, 20 with the bendingtool 4 being completely open. In this way, when the upper press beam 16is in the maximum raised position, secure covering of the space betweenthe two tool holders 19, 20 can be achieved at any time.

By means of the respective articulated mounting of the holding arms 38on the brackets 37, the holding arms 38 along with the at least oneprotective element 32 can be displaced, in particular pivoted, from theprotective position of the protective element 32 into the releaseposition of the protective element 32. The brackets 37 form first pivotaxes 41 oriented in parallel with respect to the longitudinal extensionof the upper press beam 16 and aligned with one another. Pivoting eachholding arm 38 is carried out in a pivoting plane orientedperpendicularly with respect to the pivot axes 41. Hence, the at leasttwo holding arms 38 can be pivoted between the protective position andthe release position of the at least one protective element 32, each bya pivot angle with a value selected from an angle range with a lowerlimit of 150° and an upper limit of 200°, in particular 180°.

When the protective element 32 is in the protective position, theholding arms 38 are preferable held so as to be suspended and thus beperpendicular to the brackets 37 and project in the direction towardsthe lower press beam 13. In the release position of the protectiveelement 32, these project upwards towards the side facing away from thelower press beam 13. In the release position, the at least oneprotective element 32 is arranged on the side of the holding arms 38facing away from the upper press beam 16 and so as to be suspended onthe holding arms 38 in the direction towards the lower press beam 13.

In the protective position, both the holding arms 38 starting out fromthe brackets 37 and the at least one protective element 32 connected tothe holding arms 38 in an articulated manner have a suspendedarrangement in the direction towards the lower press beam 13. Suspendedis understood to refer to the position caused by gravity.

As was described above, a second bearing point with second pivot axes 42is formed between each second end region 39 of the holding arms 38 andthe first longitudinal edge 34 of the protective element 32.

Preferably, a longitudinal extension of the holding arms 38 between thetwo end regions 39, 40, in particular the pivot axes 41, 42, formedthere in each case, approximately corresponds to the width 36 of the atleast one protective element 32 between its two longitudinal edges 34,35 in each case. However, the longitudinal extension of the holding arms38 could also be selected to be larger or smaller than the width 36.

In order to create sufficient free space without an interfering contourin the region of the bending tool, the brackets 37 are arranged on theupper press beam 16 in such manner that in the protective position andwith the bending tool 4 being completely open, the second longitudinaledge 35 of the at least one protective element 32 faces the lower pressbeam 13. The at least one protective element 32 with its secondlongitudinal edge 35 preferably extends at least to the lower toolholder 19. It proved to be beneficial if the at least two brackets 37are arranged in an upper end section of the upper press beam 16.

Further, so as to facilitate the adjusting movement and/or itsperformance, a schematically adumbrated actuator and/or damping device43 can also be provided. In this regard, the at least one actuatorand/or damping device 43 is preferably operatively connected to one ofthe holding arms 38. For damping and/or weight compensation, for examplea torsion spring, a tension spring that is connected to a holding arm 38and extends towards the upper press beam 16, or the like could beprovided. Moreover, at least one of the holding arms 38 could beconnected to a rotary drive for angular displacement. The actuatordevice can in particular serve the purpose of counterbalance adjustmentfor the actuation movements between the protective position and therelease position and vice versa to be carried out. Hence, the actuationmovements can be facilitated for the operator as regards force.

FIGS. 6 and 7 show a further possible and possibly independentembodiment of the protective unit 29 for the bending machine and/orbending press 3, wherein again equal reference numbers and/or componentdesignations are used for equal parts as in FIGS. 1 through 5 above. Inorder to avoid unnecessary repetitions, it is pointed to/reference ismade to the detailed description in FIGS. 1 to 5 above. Here, again, anadjustment track between the protective position and the releaseposition for the at least one protective element 32 as long as possibleis to be achieved. Hence, on the one hand the risk for the operator ofunintentionally reaching for the bending tool 4 to be changed orretrofitted during the tool change is minimized severely and on theother hand no interfering contour is formed during bending operation bythe protective element 32 in the region of the bending tool as well as alarge part of the upper press beam 16.

In this exemplary embodiment shown here, another possible design of anadjusting device 44 for the protective unit 29 is shown, which is why areference number differing from the previously described adjustingdevice 33 is used. The general adjustment track as well as the at leastone protective element 32 can be formed analogously, as was describedabove.

Here, instead of the lever arrangement with the brackets 37 and theholding arms 38, several linear guide arrangements 45 are provided forextending the adjustment track between the protective position and therelease position of the protective element 32. The linear guidearrangements 45 can also be referred to as telescopic guides ortelescope guide arrangements. Each of the linear guide arrangements 45comprises a first guide rail 46, a second guide rail 47 and at least onefurther guide rail 48. Depending on the constructional length of thepress beams 13, 16 and the at least one protective element 32, at leasttwo of the linear guide arrangements 45 are to provided per protectiveelement 32. Moreover, the at least two linear guide arrangements 45 arearranged at a distance from one another in the direction of thelongitudinal extension of the at least one protective element 32.

However, instead of the guide rails, telescopic cylinders, which providesufficient stroke, can also be used.

The first guide rails 46 are stationarily arranged for example on thebending press 3, in particular on its machine frame 7, however,preferably on the respective upper press beam 16, in particular mountedthereto. The at least two linear guide arrangements 45 are further heldon the upper press beam 16 in vertical orientation. The at least onefurther guide rail 48 is in each case stationarily arranged on the atleast one protective element 32, in particular mounted thereto. Thesecond guide rail 47 is in each case provided directly immediatelysuccessive to the first guide rail 46. The guide rails are each guidedon one another so as to allow for performing a defined adjustment track.

In order to achieve secure covering and a protective position in theopen position of the press beams 13, 16 a maximum adjustment track ofthe at least two linear guide arrangements 45 is to be selected suchthat in the protective position and with the bending tool 4 beingcompletely open, the second longitudinal edge 35 of the at least oneprotective element 32 faces the lower press beam 13 and the at least oneprotective element 32 with its second longitudinal edge 35 extends atleast to the lower tool holder 19.

It can further be advantageous if at least one drive element 49 isprovided on at least one of the linear guide arrangements 45. Byproviding at least one drive element 49, a controlled adjusting movementbetween at least individual ones of the guide rails 46 and/or 47 and/or48 can be achieved. For example, one of the drive elements 49 could beprovided between the first guide rail 46 and the second guide rail 47.Further or additionally to this, one of the drive elements 49 could alsobe provided between the second guide rail 47 and the at least onefurther guide rail 48.

The drive element(s) 49 can for example serve for carrying out acompulsory guide of the adjusting movement between the individual guiderails. For example, a belt drive or toothed racks with at least oneintermediate pinion or cogwheel arranged in between and beingdrive-connected would be conceivable. If the intermediate pinion orcogwheel is driven by a driving means, a drive support or an independentadjustment can be achieved.

It would further be possible, as was also already described above, toprovide an actuator and/or damping device 43. Hence, a counterbalanceadjustment can be achieved for example by means of a constant forcespring or a cylinder piston arrangement charged with constant pressure.The at least one actuator and/or damping device 43 is operativelyconnected to the at least one protective element 32 for this purpose.

The exemplary embodiments show possible embodiment variants, and itshould be noted in this respect that the invention is not restricted tothese particular illustrated embodiment variants of it, but that ratheralso various combinations of the individual embodiment variants arepossible and that this possibility of variation owing to the teachingfor technical action provided by the present invention lies within theability of the person skilled in the art in this technical field.

The scope of protection is determined by the claims. However, thedescription and the drawings are to be adduced for construing theclaims. Individual features or feature combinations from the differentexemplary embodiments shown and described may represent independentinventive solutions. The object underlying the independent inventivesolutions may be gathered from the description.

All indications regarding ranges of values in the present descriptionare to be understood such that these also comprise random and allpartial ranges from it, for example, the indication 1 to 10 is to beunderstood such that it comprises all partial ranges based on the lowerlimit 1 and the upper limit 10, i.e. all partial ranges start with alower limit of 1 or larger and end with an upper limit of 10 or less,for example 1 through 1.7, or 3.2 through 8.1, or 5.5 through 10.

Finally, as a matter of form, it should be noted that for ease ofunderstanding of the structure, elements are partially not depicted toscale and/or are enlarged and/or are reduced in size.

LIST OF REFERENCE NUMBERS

1 production installation 31 tool storage

2 workpiece 32 protective element

3 bending press 33 adjusting device

4 bending tool 34 first longitudinal edge

5 bending punch 35 second longitudinal edge

6 bending die 36 width

7 machine frame 37 bracket

8 base plate 38 holding arm

9 side wall 39 first end region

10 side wall 40 second end region

11 cross connection 41 first pivot axis

12 front end face 42 second pivot axis

13 press beam 43 actuator and/or damping device

14 front end face 44 adjusting device

15 linear guide 45 linear guide arrangement

16 press beam 46 first guide rail

17 end face 47 second guide rail

18 end face 48 further guide rail

19 tool holder 49 drive element

20 tool holder

21 driving arrangement

22 driving means

23 energy grid

24 controller

25 input terminal

26 spindle drive

27 adjusting means

28 support table

29 protective unit

30 tool manipulation unit

1. A production installation (1), in particular for air bending orbottom bending of a workpiece (2) to be manufactured from a sheet metal,comprising a bending press (3), in particular a press brake, with amachine frame (7), a lower press beam (13), an upper press beam (16) aswell as tool holders (19, 20) arranged or formed on the press beams (13,16), at least one bending tool (4) with at least one bending punch (5)and at least one bending die (6), a tool manipulation unit (30) formoving the bending tool (4) between the tool holders (19, 20) and a toolstorage (31) or for changing the position of the bending tool (4)relative to the tool holders (19, 20), a protective unit (29) with atleast one protective element (32) and an adjusting device (33, 44), bymeans of which adjusting device (33, 44) the at least one protectiveelement (32) can be displaced relative to the bending press (3) from aprotective position which at least sectionally covers the bending tool(4) into a release position which at least sectionally releases thebending tool (4), and the at least one protective element (32) isplate-shaped and comprises a first longitudinal edge (34) as well as asecond longitudinal edge (35) and a width (36) of the protective element(32) is defined by the two longitudinal edges (34, 35), and wherein theprotective unit (29) is arranged in a feed region in front of thebending press (3), wherein either the adjusting device (33) comprises atleast two brackets (37) and at least two holding arms (38) each having afirst end region (39) and a second end region (40), and the holding arms(38) each being mounted on the brackets (37) in an articulated mannerwith their first end regions (39) and the holding arms (38) each beingconnected to the at least one protective element (32) on its firstlongitudinal edge (34) facing away from the first press beam (13) in anarticulated manner with their second end regions (40), and the at leasttwo brackets (37) being arranged at a distance from one another in thedirection of the longitudinal extent of the at least one protectiveelement (32), or the adjusting device (44) comprises at least two linearguide arrangements (45), and each of the linear guide arrangements (45)comprises a first guide rail (46) and a second guide rail (47) and atleast one further guide rail (48), and the first guide rails (46) areeach arranged stationarily on the bending press (3), and each of the atleast one further guide rails (48) is mounted on the at least oneprotective element (32), and the at least two linear guide arrangements(45) are arranged at a distance from one another in the direction of thelongitudinal extent of the at least one protective element (32).
 2. Theproduction installation (1) according to claim 1, wherein the protectiveunit (29), in particular its brackets (37) or its first guide rails(46), is held on the upper press beam (16).
 3. The productioninstallation (1) according to claim 1, wherein the width (36) of the atleast one protective element (32) between its two longitudinal edges(34, 35) corresponds to an opening width between the tool holders (19,20) of the completely open bending tool (4).
 4. The productioninstallation (1) according to claim 1, wherein the at least two holdingarms (38) are pivotable between the protective position and the releaseposition of the at least one protective element (32), each by a pivotangle with a value selected from an angle range with a lower limit of150° and an upper limit of 200°, in particular 180°.
 5. The productioninstallation (1) according to claim 1, wherein a longitudinal extensionof the holding arms (38) each approximately corresponds to the width(36) of the at least one protective element (32) between its twolongitudinal edges (34, 35).
 6. The production installation (1)according to claim 1, wherein in the release position, the holding arms(38) each starting out from the brackets (37) project towards the sidefacing away from the lower press beam (13) and the at least oneprotective element (32) is arranged so as to be suspended on the side ofthe holding arms (38) facing away from the upper press beam (16) as wellas in the direction towards the lower press beam (13).
 7. The productioninstallation (1) according to claim 1, wherein in the protectiveposition, both the holding arms (38) starting out from the brackets (37)and the at least one protective element (32) connected to the holdingarms (38) in an articulated manner comprise a suspended arrangement inthe direction towards the lower press beam (13).
 8. The productioninstallation (1) according to claim 1, wherein the brackets (37) arearranged on the upper press beam (16) such that in the protectiveposition and with the bending tool (4) being completely open, the secondlongitudinal edge (35) of the at least one protective element (32) facesthe lower press beam (13) and the at least one protective element (32)with its second longitudinal edge (35) extends at least to the lowertool holder (19).
 9. The production installation (1) according to claim1, wherein the at least two brackets (37) are arranged in an upper endsection of the upper press beam (16).
 10. The production installation(1) according to claim 1 wherein at least one actuator and/or dampingdevice (43) is provided, said at least one actuator and/or dampingdevice (43) being operatively connected to one of the holding arms (38).11. The production installation (1) according to claim 1, wherein amaximum adjustment track of the at least two linear guide arrangements(45) is selected such that in the protective position and with thebending tool (4) being completely open, the second longitudinal edge(35) of the at least one protective element (32) faces the lower pressbeam (13) and the at least one protective element (32) with its secondlongitudinal edge (35) extends at least to the lower tool holder (19).12. The production installation (1) according to claim 1, wherein the atleast two linear guide arrangements (45) are held on the upper pressbeam (16) in vertical orientation.
 13. The production installation (1)according to claim 1, wherein at least one drive element (49) isprovided on at least one of the linear guide arrangements (45).
 14. Theproduction installation (1) according to claim 13, wherein one of thedrive elements (49) is provided between the first guide rail (46) andthe second guide rail (47).
 15. The production installation (1)according to claim 13, wherein one of the drive elements (49) isprovided between the second guide rail (47) and the at least one furtherguide rail (48).
 16. The production installation (1) according to oneclaim 1, wherein at least one actuator and/or damping device (43) isprovided, said at least one actuator and/or damping device (43) beingoperatively connected to the at least one protective element (32).